Appropriate mechanical strength of carbon black-decorated loofah sponge as anode material in microbial fuel cells

A new composite anode material, possessing an appropriate mechanical strength, was fabricated by depositing carbon black on the loofah sponge matrix surface. Carbon black was oxidized in nitric acid (HNO3) and hydrogen peroxide (H2O2), respectively, to increase electrochemical properties before starting deposition. Microbial fuel cell (MFC) with the H2O2 treated carbon black anode achieved the maximum power density of 61.7 ± 0.6 W/m3, which was higher than one decorated with the HNO3 treated or untreated carbon black. Scanning electron microscopy (SEM) observation showed a compact bacterial attachment on the H2O2 treated carbon black surface. Results of electrochemical impedance spectroscopy (EIS) and Tafel plots indicated a fast electron transfer rate between the H2O2 pre-treatment of carbon black and electrochemically active bacteria (EAB). Therefore, the H2O2 treated carbon black-loofah sponge anode was promising for MFC application in terms of its superior performance, straightforward fabrication method and ultra-low cost.